Objective This study investigates the Malage composite pluton in the southern Xing'an Block to clarify the spatiotemporal influence boundaries of two tectonic systems (Mongolia−Okhotsk Ocean and Paleo−Pacific) in Northeast China.

Methods We conducted systematic sampling of lithologic units within the pluton, followed by petrographic analysis, zircon U−Pb geochronology, and whole−rock geochemical characterization.

Results The Malage complex pluton comprises two granite phases. The early−stage assemblage (quartz monzonite diorite, monzogranite and alkali−feldspar granite)emplaced during the Late Triassic (225 ± 1 Ma and 220 ± 2 Ma), and granite porphyry intruded in the late Early Cretaceous (124 ± 1 Ma). Both phases represent high−K calc−alkaline I−type granites, though the Cretaceous porphyry exhibits higher differentiation. They are both characterized by enrichment of large ion lithophilic elements (Rb, Ba, K) and light rare−earth elements (LREE), different degrees of loss (Ta, Nb, P, Ti) in high field strength elements (HFSE) and heavy rare−earth elements (HREE), low total rare earths (ΣREE=34.25×10⁻⁶~217.91×10⁻⁶), variable negative Eu anomalies (δEu=0.40~0.84).

Conclusions Integrated geological evidence suggests that Late Triassic Mongolian−Okhotsk Ocean subduction influenced the southern Xing'an Block, and late Early Cretaceous magmatism occurred under an extensional regime driven jointly by post−collisional relaxation after Mongolia−Okhotsk Ocean closure and Paleo−Pacific Plate rollback, with predominant control from the latter.